As the non-magnetic single-component developing system, for example, methods described in Japanese Patent Laid Open to Public Publication (JP-A) Nos. 63-212946, 63-271374 and Japanese Patent Examined Publication (JP-B) No. 2774534 have been known. In this system, an electrostatic latent image is developed by supplying a thin layer of a non-magnetic developer onto the surface of a electrostatic latent image forming member by a developing apparatus having a developer carrying member, a toner layer regulation member and a toner supply assisting member in which the toner supply assisting member and the developer carrying member, and toner layer regulation member and the developer carrying member are respectively contacted with together to form the developer thin layer. In such the method, the non-magnetic toner is charged by friction electrification of the non-magnetic developer with developer carrying member and the toner layer regulation member.
Color electrophotographic apparatuses have a merit such as that the developing apparatus can be made compact and are widely utilized at desk side of offices, in small offices, SOHO and domestic houses. In the non-magnetic single-component developing system, the toner particles are electrically charged by passing through the gap between the developer carrying member and the toner layer regulation member arranged to be contacted with the toner layer regulation member. The toner particles receive stress on the occasion of passing through the gap between the developer carrying member and the toner regulation member. The mechanical strength of the toner particles is held by raising the softening point thereof by controlling the molecular weight thereof or giving crosslinked structure so as to prevent the crushing of the toner particles by the stress. As a result of that, the fixing temperature is raised and electric consumption is increased so that the load onto the use in the small offices, SOHO and domestic house is increased. Under such the conditions, a technique for dispersing organic polymer fine particles having high softening point and a particle diameter of not more than 0.5 μm, cf. Patent Document 1 for example, and that by which filler particles are dispersed in a thermoplastic layer covering the nucleus particles mainly composed of thermoplastic resin and colorant, cf. Patent Document 2 for example, have been known. However, such the toner particles do not satisfy the fixing ability at low temperature and anti-crushing ability.
Patent Document 1: JP-A 2-1869
Patent Document 2: JP-A 7-36213